Silicon migration seal wafer-level vacuum encapsulation

Abstract

Silicon migration seal (SMS) wafer-level packaging is proposed for high vacuum encapsulation of MEMS. The sealing of vent holes is possible based on silicon surface migration effect at 1100°C in 100% hydrogen ambient without deposition, if the size of the vent holes is properly designed. The feasibility of SMS packaging was experimentally demonstrated using 4-inch wafers. Hermetic sealing was confirmed after 168 hours from the packaging process by diaphragm displacement in the cap wafer.